Re: [PATCH kvm-unit-tests v2 4/9] arch-run: generate errata when no environ is provided

[Andrew Jones <drjones@redhat.com>]

On Thu, Jun 08, 2017 at 12:43:20PM +0200, Laurent Vivier wrote:
> On 06/06/2017 20:22, Andrew Jones wrote:
> > Provide a table mapping errata to minimum kernel versions and
> > a function that will use the host's kernel version to determine
> > the values for each errata variable. These errata variables, with
> > values based on the host kernel, are now provided to all unit
> > tests by default, if no environ is provided. Errata variables
> > passed from the run script environment still take precedence.
> > 
> > Signed-off-by: Andrew Jones <drjones@redhat.com>
> > ---
> >  configure             | 11 +++++++++++
> >  errata.txt            |  5 +++++
> >  scripts/arch-run.bash | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> >  3 files changed, 62 insertions(+)
> >  create mode 100644 errata.txt
> > 
> > diff --git a/configure b/configure
> > index 64722c9b263b..cde2cfe9db61 100755
> > --- a/configure
> > +++ b/configure
> > @@ -14,6 +14,7 @@ host=$arch
> >  cross_prefix=
> >  endian=""
> >  pretty_print_stacks=yes
> > +environ_default=yes
> >  u32_long=
> >  
> >  usage() {
> > @@ -31,6 +32,9 @@ usage() {
> >  	    --endian=ENDIAN        endianness to compile for (little or big, ppc64 only)
> >  	    --[enable|disable]-pretty-print-stacks
> >  	                           enable or disable pretty stack printing (enabled by default)
> > +	    --[enable|disable]-default-environ
> > +	                           enable or disable the generation of a default environ when
> > +	                           no environ is provided by the user (enabled by default)
> >  EOF
> >      exit 1
> >  }
> > @@ -73,6 +77,12 @@ while [[ "$1" = -* ]]; do
> >  	--disable-pretty-print-stacks)
> >  	    pretty_print_stacks=no
> >  	    ;;
> > +	--enable-default-environ)
> > +	    environ_default=yes
> > +	    ;;
> > +	--disable-default-environ)
> > +	    environ_default=no
> > +	    ;;
> >  	--help)
> >  	    usage
> >  	    ;;
> > @@ -183,5 +193,6 @@ TEST_DIR=$testdir
> >  FIRMWARE=$firmware
> >  ENDIAN=$endian
> >  PRETTY_PRINT_STACKS=$pretty_print_stacks
> > +ENVIRON_DEFAULT=$environ_default
> >  U32_LONG_FMT=$u32_long
> >  EOF
> > diff --git a/errata.txt b/errata.txt
> > new file mode 100644
> > index 000000000000..95b66c837c63
> > --- /dev/null
> > +++ b/errata.txt
> > @@ -0,0 +1,5 @@
> > +#---------------:-----------------------:--------------------------------------
> > +# commit	: minimum kernel	: summary
> > +# 12 hex digits	: version		:
> > +#---------------:-----------------------:--------------------------------------
> > +#---------------:-----------------------:--------------------------------------
> > diff --git a/scripts/arch-run.bash b/scripts/arch-run.bash
> > index 09072ee46366..b4aa67f3c94c 100644
> > --- a/scripts/arch-run.bash
> > +++ b/scripts/arch-run.bash
> > @@ -172,6 +172,8 @@ env_add_errata ()
> >  			test -v $errata && continue
> >  			eval export "$line"
> >  		done
> > +	elif [ ! -f "$ENV" ]; then
> > +		env_generate_errata
> >  	fi
> >  
> >  	if grep -q '^ERRATA_' <(env); then
> > @@ -183,6 +185,50 @@ env_add_errata ()
> >  	fi
> >  }
> >  
> > +env_generate_errata ()
> > +{
> > +	local kernel_version_string=$(uname -r)
> > +	local kernel_version kernel_patchlevel kernel_sublevel
> > +	local line commit minver errata v p s have
> > +
> > +	IFS=. read kernel_version kernel_patchlevel kernel_sublevel <<<$kernel_version_string
> > +	kernel_sublevel=${kernel_sublevel%%[!0-9]*}
> 
> I don't understand the pattern.
> 
> BASH(1)
> 
> ${parameter%%word}
>     The word is expanded to produce a pattern just as in pathname
>     expansion
> 
> Pathname Expansion
> 
>     *      Matches any string
>     [...]  Matches any one of the enclosed characters
>            If  the  first character following the [ is a !  or a ^ then
>            any character not enclosed is matched
> 
> So you need only "${kernel_sublevel%%-*}"

This assumes the kernel's EXTRAVERSION starts with a '-', which is likely
a safe assumption, but the pattern I used ensures any non-digit will be
dropped, which is safer, because kernel_sublevel gets used in arithmetic
expressions.

Thanks,
drew